[4.2] Implement verification that noescape closures passed to Objecti… #16348
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…ve-C are not escaped
The series of commit introduces a ``copy_block_without_escaping`` block
instruction that ties a swift closure sentinel to the block that is
escaped.
SILGen emits this instruction when it generates a conversion from a
``@noescape`` swift closure to a block.
```
%noescape_closure = ...
%wae_Thunk = function_ref @$withoutActuallyEscapingThunk
%sentinel =
partial_apply [callee_guaranteed] %wae_thunk(%noescape_closure)
%noescaped_wrapped = mark_dependence %sentinel on %noescape_closure
%sentinel_copy = copy_value %noescaped_wrapped
%storage = alloc_stack
%storage_address = project_block_storage %storage
store %noescaped_wrapped to [init] %storage_address
%block = init_block_storage_header %storage ...
%block = copy_block_without_escaping %block withoutEscaping %noescaped_wrapped
```
The ClosureLifetimeFixup pass then lowers
``copy_block_without_escaping`` into a ``copy_block`` and
``is_escaping``/``cond_fail``/``destroy_value`` combination at a point
that succeeds the end of the block's lifetime.
As a result whenever a semantic noescape Swift closure synchronously
escapes to Objective C we will trap with an error after we return from
the Objective C call.
rdar://39682865
Cherry-pick of swiftlang#16236
Commits:
* Add a copy_block_without_escaping %block withoutEscaping %closure instruction
Mandatory pass will clean it up and replace it by a copy_block and
is_escaping/cond_fail/release combination on the %closure in follow-up
patches.
The instruction marks the dependence of a block on a closure that is
used as an 'withoutActuallyEscaping' sentinel.
* SIL: Allow is_escaping_closure on optional closure types
* SILGen: Emit withoutActuallyEscaping verification for @NoEscape closures stored in blocks
* SIL: Add getSingleDealloc to AllocStack and remove two copies of it
I am going to introduce a third use in a follow-up
* ClosureLifetimeFixup: Add support for copy_block_without_escaping instructions
Replace:
%copy = copy_block_without_escaping %block withoutEscaping %closure
...
destroy_value %copy
by (roughly) the instruction sequence:
%copy = copy_block %block
...
destroy_value %copy
%e = is_escaping %closure
cond_fail %e
destroy_value %closure
* Fix DiagnoseStaticExclusivity
After the copy_block_without_actually_escaping change it might see a
mark_dependence instruction on a noescape closure.
* Fixes to AccessSummaryAnalysis
The pattern we see for noescape closure passed to objective c is different:
There is the additional without actually escaping closure sentinel.
* Fix test cases after SIL representation changes
* Executable test case for passing a noescape closure to Objective-c which
escapes the closure.
We expect the program to crash with an explanation.
* Distinguish between withoutActuallyEscaping and passing @NoEscape
Objective C closures when reporting that a closure has escaped
rdar://39682865
|
@swift-ci Please test |
|
Build failed |
|
@swift-ci Please test linux |
|
@eeckstein I can't merge this. Can you? |
eeckstein
approved these changes
May 3, 2018
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
…ve-C are not escaped
The series of commit introduces a
copy_block_without_escapingblockinstruction that ties a swift closure sentinel to the block that is
escaped.
SILGen emits this instruction when it generates a conversion from a
@noescapeswift closure to a block.The ClosureLifetimeFixup pass then lowers
copy_block_without_escapinginto acopy_blockandis_escaping/cond_fail/destroy_valuecombination at a pointthat succeeds the end of the block's lifetime.
As a result whenever a semantic noescape Swift closure synchronously
escapes to Objective C we will trap with an error after we return from
the Objective C call.
rdar://39682865
Cherry-pick of #16236
Commits:
Mandatory pass will clean it up and replace it by a copy_block and
is_escaping/cond_fail/release combination on the %closure in follow-up
patches.
The instruction marks the dependence of a block on a closure that is
used as an 'withoutActuallyEscaping' sentinel.
SIL: Allow is_escaping_closure on optional closure types
SILGen: Emit withoutActuallyEscaping verification for @NoEscape closures stored in blocks
SIL: Add getSingleDealloc to AllocStack and remove two copies of it
I am going to introduce a third use in a follow-up
Replace:
%copy = copy_block_without_escaping %block withoutEscaping %closure
...
destroy_value %copy
by (roughly) the instruction sequence:
%copy = copy_block %block
...
destroy_value %copy
%e = is_escaping %closure
cond_fail %e
destroy_value %closure
After the copy_block_without_actually_escaping change it might see a
mark_dependence instruction on a noescape closure.
The pattern we see for noescape closure passed to objective c is different:
There is the additional without actually escaping closure sentinel.
Fix test cases after SIL representation changes
Executable test case for passing a noescape closure to Objective-c which
escapes the closure.
We expect the program to crash with an explanation.
Objective C closures when reporting that a closure has escaped
rdar://39682865
Replace this paragraph with a description of your changes and rationale. Provide links to external references/discussions if appropriate.
Resolves SR-NNNN.